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<\/p>\nThe use of appropriately functionalized molecular building blocks to form novel nano-architectures with tailored structure and electronic properties has recently been brought under the spotlight. Recently, the ESISNA\u00a0group has developed\u00a0an effective way of\u00a0exploiting on-surface chemistry to grow different\u00a0nanostructures\u00a0in\u00a0sequential steps from the same molecular precursor. We have used\u00a0different activation temperatures to control the on-surface C\u2013H bond\u00a0breaking and C\u2013C bond making processes in the paradigmatic case of the nomplanar helically chiral pyridil-disubstituted\u00a0dibenzo[5]helicene (1 in figure)\u00a0deposited\u00a0on Pt(111).<\/p>\n
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This molecule experiences dehydrogenation from\u00a0different groups at different temperatures.<\/p>\n
At 440 K it cyclodehydrogenates, by cleaving some internal C\u2013H bonds, which\u00a0subsequently close to form additional carbocycles, giving rise to\u00a0N-doped nanohelicenes (2 in figure). Further annealing at 650 K cyclodehydrogenates\u00a0the aza-aromatic groups to form N-d oped nanographenes (3 in figure),\u00a0and finally, at 770 K rim-dehydrogenation leads to N-doped nanodomes (4 in figure) covalently bound to the metal surface. By an efficient\u00a0combination of the most advanced\u00a0room temperature (RT) ultra-high vacuum scanning\u00a0tunneling calculations\u00a0based\u00a0on improved density functional theory (DFT), the sequential development\u00a0microscopy (UHV-STM) technique with state-of-the-art first-principles of the different resultant structures has been monitored.<\/p>\n
Importantly, we have found significant\u00a0agreement between experimental\u00a0and calculated STM images of key intermediates, which allows\u00a0a detailed mapping of the individual steps of this complex on-surface transformation.<\/p>\n
This adequate\u00a0combination\u00a0of experiments and theory will permit shed some light in any other thermo-induced on-surface reaction of this kind.<\/p>\n
The results have been published in Chemical Communication 50, 1555-1557 (2014)<\/span>.<\/strong><\/a><\/p>\n